Information disclosure via string-builder integer overflow
Published May 14, 2026 · Updated May 14, 2026
Integer overflow in simdjson before 4.6.4 allows remote attackers to read out-of-bounds process memory via very large builder strings. string_builder::escape_and_append() miscalculates the required buffer size when size_t arithmetic wraps, leaving SIMD routines to read beyond an undersized allocation. The path requires a 32-bit build and an application that passes attacker-influenced, very large strings to the document-builder API; other reported effects are memory corruption or malformed JSON output.
Summary
What happened
Integer overflow in simdjson before 4.6.4 allows remote attackers to read out-of-bounds process memory via very large builder strings. string_builder::escape_and_append() miscalculates the required buffer size when size_t arithmetic wraps, leaving SIMD routines to read beyond an undersized allocation. The path requires a 32-bit build and an application that passes attacker-influenced, very large strings to the document-builder API; other reported effects are memory corruption or malformed JSON output.
The record
- CVE
- CVE-2026-8295
- Published
- May 14, 2026
- Updated
- May 14, 2026
- Vendor
- simdjson
- Product
- simdjson
- Classifications
- CWE-190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 14, 2026CVE publishedPublication date reported by the CVE source.
- May 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <4.6.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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